Docker Interview Questions and Answers

What is Docker?Docker is a platform to run each application isolated and securely. Internally it achieves it by using kernel containerization feature.What is the advantage of Docker over hypervisors?Docker is light weight and more efficient in terms of resource uses because it uses the host underlying kernel rather than creating its own hypervisor. What is Docker ImageDocker Image is the source of the docker container. In other words, docker images are used to create containers. It is possible create multiple isolated containers from a single image.What is Docker ContainerDocker Container is the instantiation of docker image. In other words, it is the run time instance of images. Images are set of files whereas containers is the one who run the image inside isolated.Difference between Docker Image and container?Docker container is the runtime instance of docker image.Docker Image doesnot have a state and its state never changes as it is just set of files whereas docker container has its execution state.Hello friends, as you have requested for more interview questions with answers on Docker, here are the follow-up of second part series.How do you create docker image?Docker image are created using Docker file. Docker build is command to create docker image out of docker fileSo you have the docker image, what is the next step?With docker image, we can spawn as many containers as needed. All containers can be same instance or it can also be different instance, what I mean that if we are using the same command for creating multiple containers, all container will behave as same. However, if you choose different command to create container out of same image, it will provide different functionality altogether.How to create docker container?We can create docker container by running this commanddocker run -t -i <image name> <command name>This will create and start the containerHow to know the container status?Just fire docker ps -a to list out all running container with stauts (running or stopped) on a hostHow to stop and restart the container?To stop container, we can use docker stop <container id>To start a stopped container, docker start <container id> is the commandTo restart a running container, docker restart <container id>That's all for Docker Interview Questions. I will keep posting more questions with more depth analysis.